Embodiments of the invention relate to an image sensor and a method for manufacturing the same.
An image sensor is defined as a semiconductor device converting an optical image into an electrical signal. Representative image sensors of the related art include a charge coupled device (CCD) and a CMOS image sensor, etc.
The image sensor may be manufactured according to the following process.
First, transistors and a photodiode electrically connected to one or more of the transistors are formed on a semiconductor substrate, and an insulating layer structure and wiring are formed on or over the transistors and the photodiode. Continuously, a color filter layer formed of red, green, and blue filters is formed on the insulating layer structure, and a positive type photoresist layer is applied to the upper surface of the color filter layer to form a planarization layer. Thereafter, a photoresist layer is applied to the upper surface of the planarization layer and patterned, and then a reflow process is performed to form a microlens providing light condensed in the photodiode.
The microlens is formed by forming a photoresist layer on the planarization layer and patterning it. However, when the microlens is formed by patterning the photoresist layer as described above, a gap of about 100 nm to 200 nm is formed between the microlenses so that light is incident through the gap, having a problem that the image quality may be less than optimal or ideal.